1. Technical Field
This invention relates to a high-power, high-frequency discharge pumping laser device used for effecting a machining operation such as cutting metal or the like, and more particularly, to a high-frequency discharge pumping laser device capable of maintaining a stable discharge condition while the laser output is held at zero.
2. Background Art
A high-frequency discharge pumping laser device can produce a single mode high power laser beam, and thus is widely used for the machining of metals or the like. In such a high-frequency discharge pumping laser device, the oscillation of the laser is controlled in accordance with a machining program or the like, whereby the oscillation of the laser is set to the base discharging mode while the machining operation is not effected, even when in the operative condition, and a shutter is opened in response to a machining command to start the oscillation operation of the laser with a preset power, to effect the machining operation.
Therefore, the discharge tube must be held in the base discharging state in the machining stand-by mode, and accordingly, in the prior art, auxiliary discharge electrodes are used to effect only a discharging operation with a zero output power.
For this purpose, auxiliary electrodes other than the electrodes for effecting the laser excitation must be used, and thus the construction of the discharge tube becomes complex. Further, a power supply for the auxiliary electrodes is required, and thus the construction of the high-frequency power supply for the laser pumping also becomes complex.
In addition, it is difficult to set the laser output power to zero and continuously effect only the discharging operation by using only the main electrodes for the laser excitation, without using the auxiliary electrodes.